四氟化硅生产工艺研究进展

四氟化硅作为生产多晶硅及其衍生物的原料,随着电子工业的发展以及硅基产业的扩大,对于四氟化硅的需求量逐渐增加。对四氟化硅生产工艺的研究越来越引起人们的重视。详细介绍了制备四氟化硅的4种方法,含硅源物质与含氟基团物质合成法、氟硅酸盐热解法、氟硅酸法、硫酸法,综述了国内外制备四氟化硅的研究进展情况,并评述了各工艺的特点。就目前研究表明,四氟化硅制备工艺需向环保、节能、高收率方向发展。     

四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

四氟化硅的工艺研发及进展状况

四氟化硅是电子工业中的一种重要原料,随着多晶硅等行业迅猛发展需求量逐渐增大。详细介绍了四氟化硅的应用及市场情况,并对氟气合成法、氟硅酸盐热解法、硫酸法、氢氟酸直接反应法这4种主要生产方法进行详细论述,讨论了各工艺方法的生产原理、工艺简述、研究状况并对工艺的优缺点进行了评价。就目前市场形势分析,国内四氟化硅需开发高端产品,以适应市场需求和参与国际竞争。     

双氦离子化气相色谱仪分析四氟化硅气体中微量杂质

介绍了一种利用双通道氦离子化气相色谱仪(PDHID),分析四氟化硅中微量硅烷、磷烷、氟代烷、C2～C3碳氢化合物以及常见气体杂质的方法.由于四氟化硅具有很强的腐蚀性,在对其进行分析时,利用阀切割系统将大量的四氟化硅主要成分切割,及时地将四氟化硅反吹出去,使其不进入检测器系统.经过将四氟化硅气体进样检测验证,该方法能够有效测定四氟化硅气体中多种微量杂质.     

特殊电子气-四氟化硅分析检测

四氟化硅是一种重要的特殊电子气体,可用于电子和半导体行业,高纯度的四氟化硅还可作为非晶体硅、硅烷、多晶体硅、光纤等制备的原料,文章介绍了四氟化硅气体中气体杂质、金属杂质及碘的分析检测方法,初步确定了四氟化硅气体中的杂质分析。     

四氟化硅的制备与纯化

四氟化硅是一种重要的特种气体,应用前景广阔。详细介绍了四氟化硅的性质、应用、制备方法及纯化方法,指出了每种制备方法及纯化方法的优缺点,并指明了后续的研究方向。     

四氟化硅气体中杂质的检测方法

介绍了四氟化硅气体中几类杂质的检测方法,主要包括气相色谱法、傅里叶变换红外光谱法、质谱法和微波波谱法。用气相色谱仪可以检测出四氟化硅中气体中C1~C4碳氢化合物;用高分辨率傅里叶变换红外光谱仪可以检测出SiF3OH,HF,SiF3H,SiF2H2,SiH3F,CO2,CO等气体杂质;用微波波谱仪可以检测出四氟化硅中CHF3,CH2F2,CH3F等气体杂质;用质谱仪可以检测出四氟化硅中SiF3H,SiF2H2,SiF3OSiF3等气体杂质。通过对比得出每种检测方法的优点和缺点。     

氟硅酸钙热解制备四氟化硅的工艺研究

针对四氟化硅的行业需求,本研究探讨了由磷肥副产物氟硅酸制备的氟硅酸钙热解生成四氟化硅的工艺条件,通过正交实验分析获得了适用于工业生产的氟硅酸钙最优脱水及热解条件,并对制备的粗品四氟化硅、副产品氟化钙与市售产品进行了质量指标对比,本实验所得的目标产物和副产物均满足行业的质量要求.该工艺具有流程短、能耗低、对环境危害小的特...     

高纯四氟化硅的制备技术研究进展

四氟化硅是一种有机硅化合物合成材料,被广泛应用于半导体行业,其需求量日益扩大,对其纯度要求也越来越苛刻。本文介绍了四氟化硅常用制备方法及其优缺点,列举了四氟化硅的纯化方法。在实际生产过程中,企业需根据自身实际生产情况选择合理的生产路线,结合制备工艺中杂质种类,选择合适纯化方法,获得高纯四氟化硅产品。     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.